JPS61240868A - Controller of synchronous motor - Google Patents

Abstract

PURPOSE:To control the rotating direction of a synchronous motor with a simple structure by controlling a switching element by a zero-cross signal of a power source voltage for energizing the motor. CONSTITUTION:A zero-cross signal generator 104 detects the zero potential with respect to the sinusoidal waveform of a power source voltage 105 for energizing a synchronous motor 103. A microcomputer 102 controls a triac 102 on the basis of the output of the generator 104 to control the energization of the motor 103. At this time, when the motor 103 is again energized from a point when the odd times of a (The half period of the voltage waveform) is elapsed from the time when the motor 103 is stopped, it rotates in the same direction as before stopping. When energizing after the even times of a is elapsed, it rotates reversely to before stopping.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for a synchronous motor of, for example, an electric fan.

2. Description of the Related Art Conventionally, a control device for a synchronous motor of this type has a configuration as shown in FIG. In Fig. 4, 1 is the rotor of the synchronous motor, 2 is a part of a magnetic pole sensor that detects the magnetic pole of the rotor 1 at a specific position of the rotor 1, and 3 is a triac 4 that controls whether or not the synchronous motor is energized. It is a microcomputer, 6 is a zero cross signal generating section of a power supply voltage 7, and 6 is a coil that together with a rotor constitutes a synchronous motor.

In the above configuration, the magnetic poles of the rotor 1 and the power supply voltage 7
There is the following relationship between the positive and negative values of the sine wave. If the rotor 1 stops at the N pole and the sine wave of the power supply voltage 7 at that time is positive, and this time the sine wave of the power supply voltage starts with a positive again, the rotor 1 will stop and the previous rotation will continue. The rotor 1 starts rotating in the opposite direction, but contrary to the above, if it starts with a negative sine wave of the power supply voltage, the rotor 1 rotates in the same direction as before stopping. It controlled the direction of rotation of a synchronous motor.

Problems to be Solved by the Invention In such a conventional configuration, it is necessary to install a magnetic pole sensor 2, and a synchronous motor consisting of a rotor 1 and a coil 6.
The problem was that it became complicated.

The present invention is intended to solve these problems, and aims to control the rotational direction of a synchronous motor without making any changes to the synchronous motor itself.

Means for Solving the Problem In order to solve this problem, the present invention includes a control section that controls whether or not to energize the synchronous motor, and the control section includes a control section that directly energizes the synchronous motor. A triac is used as the switch to drive the triac, and in order to drive the triac, there is a microcomputer that outputs a gate signal to the triac, and a zero time signal generator that outputs a zero cross signal of the power supply voltage to the microcomputer. This is to control the rotational direction of the synchronous motor.

Operation This configuration allows for reversal of the synchronous motor.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 to 3.

In FIG. 1, 102 is a microcomputer 101
104 is a zero-cross signal generator that detects zero potential with respect to the sine waveform of the power supply voltage 105 that is applied to the synchronous motor 103. be.

In the above configuration, what is shown in FIG. 2 shows the power supply voltage waveform A and the zero cross signal B, but the power supply voltage waveform A and the current waveform C flowing through the synchronous motor 103 are
As shown in FIG. 3, the voltage waveform A leads the current waveform C by a time difference, and the waveform B in FIG. Since it is a zero cross from , it is necessary to replace it with the phase of current waveform C. As shown in the conventional example,
Regarding the relationship between the voltage waveform and the magnetic poles of the rotor, if we infer the magnetic poles of the rotor from the current waveform, and the current waveform is inferred from the voltage waveform, rotation will occur at the zero-crossing signal of the power supply voltage waveform. The child's magnetic pole can be determined. So the second
Assuming that a half period of the voltage waveform A in the figure is a unit, if the synchronous motor 103 is stopped and the synchronous motor 103 is turned on again after this odd number of times has elapsed from the 9th point, the rotation direction will be the same as before stopping. The machine rotates in the same direction. If the synchronous motor is started to be energized again after an even number of times a has elapsed, it will rotate in the opposite direction to the direction of rotation before it stopped. Tsumashi, stop section: axml...
・・・・・・Reverse rotation axTn2・・・・・・・・・Forward rotation m: Even number m2: Odd number Also, in this case, the rising edge and falling edge of the zero cross signal generation section 104 are detected by the microcomputer-01, The period of the power supply voltage 106 is input, and based on that information, the microcomputer 101 issues a gate signal for the triac 102, and the synchronous motor 10
Control 3.

Therefore, the rotational direction of the synchronous motor can be controlled without changing the synchronous motor 103 itself.

Effects of the Invention As described above, according to the present invention, a conventional synchronous motor can be used as it is without changing the synchronous motor itself by using a magnetic pole sensor or the like to detect the magnetic poles of the rotor. , since it controls the rotational direction of the synchronous motor, it has the effect of simplifying the configuration.

[Brief explanation of drawings]

FIG. 1 shows a synchronous motor control device according to an embodiment of the present invention. 7'Owa. Circuit diagram, Fig. 2 is a waveform diagram of the power supply voltage waveform and zero-cross signal waveform of the same circuit, Fig. 3 is a voltage and current waveform diagram of the terminals of the synchronous motor, and Fig. 4 is a block circuit diagram of a conventional synchronous motor control device. It is. 101...Microcomputer, 102...
... Triac, 103 ... Synchronous motor, 104 ... Zero cross signal generation section. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure (at-
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Claims (1)

[Claims] a switching element connected in series to a synchronous motor; a switching element that energizes the synchronous motor; and a zero-cross signal generation section that outputs a zero-cross signal of a power supply voltage that energizes the synchronous motor; A control device for a synchronous motor, comprising a control section that controls the switching element using a signal.